Megan gained a BA in Architectural Glass at Swansea Metropolitan University and received the Worshipful Company of Glaziers Award for Excellence in 2010, before completing an
MA in Stained Glass Conservation and Heritage Management at the University of York. She has previously worked at the Burrell Collection, Glasgow, and Reyntiens Glass Studio, London
and is currently working as a conservator for York Glaziers Trust.

The demands of patrons for artistic displays of status and wealth challenged medieval glaziers to devise techniques for the creation of multiple colours on a single piece
of glass. 1 Over time this led to increasingly creative responses, including a variety of so-called ‘jewel’ techniques, such as annealed jewels, evident from the twelfth century,
and those wrapped in lead and inserted into a hole in glass, which were prolific in the late fifteenth and early sixteenth century. 2 The term ‘jewel’ in stained glass can be
misleading as it has commonly been used to refer to a variety of similar, yet distinctly different techniques, in addition to its descriptive use regarding iconography. The
distinction between imagery and technique has often been blurred, resulting in confusion, which has arguably been compounded by a lack of research in this area.

This paper aims to address this by assessing issues of terminology and typology, and proposing a clearer nomenclature, to help improve the identification of different ‘jewel’
techniques. These include annealed ‘jewels’ attached to the glass surface using paint, glass ‘jewels’ inserted into glass of another colour and secured with either lead or glass
paint, and glass ‘jewels’ applied to the surface using early glues or glass powders (Fig. 1-3). It is hoped this will lead to better recognition of these fascinating, yet often
overlooked, decorative techniques, and some of the conservation challenges they pose.

Figure 2 Glass 'jewels' inserted into a hole in another piece of glass and secured with glass paint. The Burrell Collection panel 45.313. Reproduced courtesy of Glasgow Museums, the Burrell Collection.

Having clarified the terminology required, the historical, cultural and symbolic influences on the choice of technique implemented by glaziers will be explored, and their impact
on the development of ‘jewel’ techniques considered. The intrinsic link between developments in these techniques and those in stained glass creation and tool technology will also
be demonstrated. This touches upon, but is not limited to, enamels, flashed glass production, abrasion and acid etching techniques, all of which affected the medieval glaziers’
options when translating designs into stained glass. <

Figure 3 Blue glass 'jewel' inserted into a hole in another piece of glass and secured with lead. The Burrell Collection panel 45.294. Reproduced courtesy of Glasgow Museums, the Burrell Collection.

In summary, this paper hopes to demonstrate the glaziers’ skill in their use of ‘jewel’ techniques to embellish the surface of the glass, whilst shedding light on some of the methods
by which they were created and proffering a theory as to why different methods were preferred, or occurred at different times.